To the Editor:—
It was with great Fig. 1. Cervical soft tissue study of a 63-yr-old morbidly obese man (123 kg, 170 cm, body mass index = 43 kg/m2) with obstructive sleep apnea, difficult mask ventilation, and difficult intubation. Atlanto-occipital gap = 0 mm; very long mandibulohyoid distance = 43 mm (normal male mean, 21 mm); unusually rostral mandibular angle at upper C2 (normal level, lower C2 or C2–C3); unusually caudally positioned hyoid at lower C4 (normal level, C3–C4). Radiography confirms the presence of a relatively short mandibular ramus and a caudally positioned hyoid. A large hypopharyngeal tongue is evident. Also note the markedly reduced posterior airway space and increased prevertebral soft tissue caused by the coexisting obesity. interest that we read the article by Langeron et al. 1published in the May 2000 issue of Anesthesiology. This was a well-designed study evaluating the incidence of difficult mask ventilation during the induction of general anesthesia in a general adult population. The authors emphasize the significant frequency of difficult mask ventilation (5%) in their study and its potential relation with difficult intubation; they also define an easy and simple clinical criteria to detect difficult mask ventilation. 2This study was performed in a French university hospital. However, the authors provided no data regarding the degree of clinical experience or years of training of the anesthesiologists involved in the study. In addition, clinical case loads for individual anesthesiologists differ a great deal within France, from 300 patients per year in some public hospitals to 120 per year in some private institutions. 3,4I suggest that the rate of clinical activity of the practitioners may influence the “diagnosis” of difficult mask ventilation and perhaps may lead to an overestimate of its incidence in comparison with previous studies. 5Regardless of these concerns, the five criteria defined by Langeron et al. 1now must be considered along with others’ airway assessment in the preoperative assessment of patients.